mirror of https://github.com/k3s-io/k3s
107 lines
3.2 KiB
Go
107 lines
3.2 KiB
Go
/*
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Copyright 2018 Google LLC
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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https://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package cloud
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import (
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"context"
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"time"
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"github.com/GoogleCloudPlatform/k8s-cloud-provider/pkg/cloud/meta"
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)
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// RateLimitKey is a key identifying the operation to be rate limited. The rate limit
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// queue will be determined based on the contents of RateKey.
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type RateLimitKey struct {
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// ProjectID is the non-numeric ID of the project.
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ProjectID string
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// Operation is the specific method being invoked (e.g. "Get", "List").
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Operation string
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// Version is the API version of the call.
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Version meta.Version
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// Service is the service being invoked (e.g. "Firewalls", "BackendServices")
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Service string
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}
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// RateLimiter is the interface for a rate limiting policy.
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type RateLimiter interface {
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// Accept uses the RateLimitKey to derive a sleep time for the calling
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// goroutine. This call will block until the operation is ready for
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// execution.
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//
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// Accept returns an error if the given context ctx was canceled
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// while waiting for acceptance into the queue.
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Accept(ctx context.Context, key *RateLimitKey) error
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}
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// acceptor is an object which blocks within Accept until a call is allowed to run.
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// Accept is a behavior of the flowcontrol.RateLimiter interface.
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type acceptor interface {
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// Accept blocks until a call is allowed to run.
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Accept()
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}
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// AcceptRateLimiter wraps an Acceptor with RateLimiter parameters.
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type AcceptRateLimiter struct {
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// Acceptor is the underlying rate limiter.
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Acceptor acceptor
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}
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// Accept wraps an Acceptor and blocks on Accept or context.Done(). Key is ignored.
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func (rl *AcceptRateLimiter) Accept(ctx context.Context, key *RateLimitKey) error {
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ch := make(chan struct{})
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go func() {
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rl.Acceptor.Accept()
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close(ch)
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}()
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select {
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case <-ch:
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break
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case <-ctx.Done():
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return ctx.Err()
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}
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return nil
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}
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// NopRateLimiter is a rate limiter that performs no rate limiting.
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type NopRateLimiter struct {
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}
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// Accept everything immediately.
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func (*NopRateLimiter) Accept(ctx context.Context, key *RateLimitKey) error {
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return nil
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}
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// MinimumRateLimiter wraps a RateLimiter and will only call its Accept until the minimum
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// duration has been met or the context is cancelled.
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type MinimumRateLimiter struct {
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// RateLimiter is the underlying ratelimiter which is called after the mininum time is reacehd.
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RateLimiter RateLimiter
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// Minimum is the minimum wait time before the underlying ratelimiter is called.
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Minimum time.Duration
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}
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// Accept blocks on the minimum duration and context. Once the minimum duration is met,
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// the func is blocked on the underlying ratelimiter.
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func (m *MinimumRateLimiter) Accept(ctx context.Context, key *RateLimitKey) error {
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select {
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case <-time.After(m.Minimum):
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return m.RateLimiter.Accept(ctx, key)
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case <-ctx.Done():
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return ctx.Err()
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}
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}
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